doc: fix typo in using-internal-errors.md

Change "messasge" to "message".

PR-URL: #14429
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

doc/guides/using-internal-errors.md

@@ -70,7 +70,7 @@ codes.
 ## Testing new errors
 
 When adding a new error, corresponding test(s) for the error message
-formatting may also be required. If the messasge for the error is a
+formatting may also be required. If the message for the error is a
 constant string then no test is required for the error message formatting
 as we can trust the error helper implementation. An example of this kind of
 error would be: